The J-Type Zaku II was built specifically for operations on Earth and lacked the proper equipment to operate in space, unlike the F-Type which could do both. The J-Type model had all its vernier thrusters apart from the two main thrusters on its backpack removed. It also featured a slightly more powerful reactor to assist in its mobility under the full-gravity conditions of Earth. Lastly, it was also better insulated against its environment, and could be used in brief underwater operations. However, the J-Type Zaku II was eventually replaced by the better designed MS-07B Gouf and MS-09 Dom mobile suits.